Grow a spring flower cascade of wisteria
Wisteria is a floriferous climber provided you prune it well
Certain plants capture the sublime moment when spring slides into summer, and wisteria is one of the finest. This woody climber usually has racemes of scented, mauve-lavender flowers that can either cascade down walls or frame a pergola, although there are blue, pink and white-flowered forms, too. They’re all members of the pea family and fix their own nitrogen at the roots, as all legumes do.
There are only four species of wisteria in all. Three occur in Asia and one in eastern USA. In the wild, wisterias are often found close to streams, wet woodlands and damp cliffs. They readily hybridise so there’s plenty of choice, although white-flowered forms brown easily and fade badly after a late frost.
Wisterias are slow-fuse, long-lived plants and their framework needs time to mature after planting. In Japan there are wisterias that may be centuries old. The UK’s oldest surviving specimen of Wisteria sinensis is in Bicton Park at Budleigh Salterton in Devon, thought to have been planted in 1837 on the advice of Scottish botanist and author John Claudius Loudon. Other veterans can be found at Kew Gardens and at Heligan in Cornwall.
Chinese Wisteria sinensis produces its flowers on bare wood and the stems twine anticlockwise. Japanese W. floribunda, from which most garden forms have been developed, twines in a clockwise direction and has leaves and flowers at the same time. A simple way to remember this is to form the letter J (for Japanese) with the finger and thumb of your right hand, starting at the top. Your fingers will form the J in a clockwise direction, whereas if you form a letter C with your left hand, your fingers move anticlockwise!
Top growing tips
■ When feeding in spring, use a high-potash feed such as Vitax Q4 or rose fertiliser, not a nitrogen-rich one. Potash promotes flower, but adding nitrogen to leguminous plants promotes leaf at the expense of flower.
■ Wisterias are sun lovers but sensitive to spring frosts, so grow against a south-facing wall if possible, so they can benefit from the warmth and sunshine. They’ll also flower on west-facing walls, although not as prolifically and blooms tend to arrive later.